555

Not sure what you want with 555. Do you want math problems, or something about 555 timer electronics, or base conversions? Here are quick math facts and a tiny practice set to get you started:

Quick facts about 555 (math)

• Prime factorization: 555 = 3 × 5 × 37
• Divisors: 1, 3, 5, 15, 37, 111, 185, 555
• Number of divisors: 8
• Decimal to binary: 555 = 1000101011₂
• Decimal to octal: 555 = 1053₈
• Decimal to hex: 0x22B
• Sum of digits = 15, so 555 is divisible by 3 and by 5; 555 ÷ 15 = 37

Quick practice problems (number theory / basic algebra)

1. Verify the prime factorization and list all divisors.
2. What is 555 modulo 9? What about modulo 7?
3. If d is a divisor of 555 with d > 1, what are the possible values of d?
4. Find 555 in base 4 (decimal to base 4).

If you meant something else (like the 555 timer IC, or a different subject), tell me the topic and your exam level, and I’ll tailor a quick study set.